Process for depositing a water insoluble 
bactericide on a fabric



March 9, 1965 P. v. PANO ETAL 3,172,777 PROCESS FOR DEPOSI'TING A WATERmsowsw BACTERIOCIDE ON A FABRIC Filed April 10, 1963 Inventors PcTer If.Pawo I ld'duum R. Fiucefie M 9. 9M 12m jfuzzb Prlio melts United StatesPatent 3,172,777 PROCESS FOR DEPOSITING A WATER INSOLUBLE BACTERIOCIDEON A FABRIC Peter V. Pane, Miami Shores, Fla, and William A. Faucette,Wheaten, 11L, assignors to Linen Supply Association of America, Miami,Fla, a corporation not for profit of Illinois Filed Apr. 10, 1963, Ser.No. 271,995 4 Claims. (Cl. 117-1385) The present invention relates tomeans for preventing growth on a fabric.

In the normal use of fabrics, such as toweling, in industrial orcommercial service, or the like, one of the more importantconsiderations is the prevention of growth upon the fabric. Preventionof such growth will prolong the effective useful life of the fabric. Inthe use of towels in commercial service, for example, it is customaryfor the users thereof to place the towel in a receptacle after use andto permit the towel to remain in the container for extended periodsuntil the need for subsequent use arises. In view of the fact that thefabric normally is stored in a moist condition in warm areas, theconditions are especially conducive to growth on the surface of thefabric.

When the towel or fabric becomes soiled it will normally be discardedinto a suitable receptacle and will remain in such receptacle until sentto a laundering service for cleansing. There usually will be anaccumulation of towels within the receptacle and conditions therein aresuch that the growth of fungi, bacteria, etc. is considerably enhancedif the fabric has not been treated to retard or prevent such growth.

When the fabric is laundered subsequently, it often is difiicult toremove all traces of the growth from the fabric, and as a result, ratherlarge laundering expenses may be encountered in attempting tosatisfactorily cleanse soiled fabric. Further, uncontrolled growth uponthe fabric will lead to premature deterioration of the fabric renderingit unsuitable for continued use and thus making it necessary to replacethe fabric.

In view of this characteristic, it is necessary to treat the surface ofthe fabric in a manner adapted to retard or wholly prevent growththereon at least for the period from one laundering to the next. Themeans employed to treat the fabric must not be water soluble due to thefact that from time to time, in use, the fabric, will be rinsed in aWater solution or may be employed to wipe up water solutions. If thegrowth preventing means were soluble in such solutions it would beeliminated from the fabric at an early stage and thus be ineffective inpreventing growth. The means must be fairly stable in order to beretained on the fabric for the normal periods and conditions of use.

The process employed heretofore for depositing a growth preventingmeans, such as a mildicide, upon the fabric, involved placing the growthpreventative into the last rinse of the laundering cycle and thendepending upon deposit of the material upon the fabric during this rinsecycle. It can readily be seen that, for several reasons, this process isnot totally satisfactory. The amount of mildicide required, for example,in the large volume rinse bath must be relatively large in order tobuild up the concentration therein to a level suitable to givereasonable assurance of deposition of the requisite amount of theeffective ingredient of the growth preventing solution upon the surfaceof the fabric. Such process, further, is very inefficient in that it isdifiicult to control the character of the solution and a large amount ofthe material in solution is lost at the end of each cycle when the rinsewater is disposed preparatory to subsequent laundering cycles. It hasbeen estimated that approximately to of the effective growth preventingmeans within the rinse bath is lost (depending upon the character of thesolution) when the bath is drained from the laundering apparatus at theend of each cycle. In an industry where economy of operation is a veryiI'IlPOl? tant factor, such wastefulness is of a character thatidentifies the specific area of the process as unsatisfactory anddictates that improvement be made.

In accordance with the present invention an improved means forprevention of growth upon a fabric is employed that is highly eflicientin operation. The process is effected by spraying a growth preventingmeans upon the surface of a fabric and then permitting the means toprecipitate upon the surface after solution deposition thereon.

It is, therefore, a general object of the present invention to providean improved process for the treatment of fabrics for the prevention ofgrowth thereon.

It is an additional object of the present invention to provide animproved process for the treatment of fabrics for the prevention ofgrowth thereon which process in volves the spraying of a growthpreventing compound thereon during one stage of said processing cycle.

A further object of the present invention resides in the provision of animproved process for the treatment of fabrics which process involves thespraying of a mildicide upon the surface of a fabric after thelaundering of saidfabric and prior to the ironing thereof.

Still a further object of the present invention resides in the provisionof a method for the treatment of fabrics which process includes thespraying of a mildicide upon the fabric in the form of a solution andprecipitating the effective portion of the solution upon the fabricduring the ironing cycle of the process.

An additional object of the present invention resides in the provisionof an improved method for the treatment of fabrics which processincludes the spraying of'phenylmercuric acetate upon the fabric in theform of a solution and precipitating the effective mildicide from thesolution upon the fabric during the ironing cycle of the process.

Another object of the present invention is to provide a process for thetreatment of 'fabric wherein a growth preventing solution having aneffectivegrowth' preventing means therein in solution at alkaline pHvalues is sprayed upon said fabricand is precipitated upon said fabricupon the subsequent application of heat thereto.

A further object of 'the present invention is to provide an alkalinesolution of sodium pentachlorophenate income bination with a latent acidin which the acid becomes elfec tive upon the application of heatthereto to release free pentachlorophenol from solution.-

Still another object of the present invention resides in the provisionof an improved process for the treatment of fabrics employing analkaline solution of sodium pentachlorophenate in combination with alatent acid in which the acid is released in solution upon applicationof heat to said solution and wherein the acid is effective toprecipitate free pentachlorophenol from solution and to deposit it uponthe surface of the fabric to be treated.

An additional object of the present invention resides in the provisionof a process for the treatment of fabrics which includes spraying saidfabric with a solution containing a mildicide adapted to be precipitatedupon the fabric upon application of heat to said solution treatedfabric.

The novel features which we believe to be characteristic of ourinvention are set forth with particularity in the-appended claims. Ourinvention itself, however, together with further objects and advantagesthereof, will best be understood by reference to the followingdescriptions taken in connection with the accompanying drawings, inwhich:'

FIGURE 1 is a schematic representation of the process of the presentinvention illustrating the spraying and heating cycles of said process;

FIGURE 2 is a fragmentary view of the spray cabinet illustrating thespraying cycle in greater detail; and

FIGURE 3 is a fragmentary view of the conveyor belt utilized in thespraying cycle.

Referring more particularly now to FIGURES 1, 2 and 3 of the drawings,there is shown a laundering apparatus, indicated at 10. The launderingapparatus would be included in the industrial towel service specificallyto cleanse the soiled fabric prior to spraying of the growthpreventative thereon. It should be observed, however, that in theapplication of the process of the present invention to any other fieldit would be desirable to cleanse the material prior to application ofthe growth preventative for most effective results.

The cleansed, but still wet, fabric is transported from the launderingapparatus to the conveyor, indicated generally at 12 to be transportedtherealong through the subsequent operations. The conveyor 12 includes aconveyor belt 14 which is of woven net-like construction to permitpassage of liquids therethrough and to provide an adequate support forthe materials to be transported thereon. A fragmentary section of theconveyor belt 14 is illustrated in FIGURE 3. The belt 14 is drivinglyengaged by conveyor rolls 16 and 18. The roll 16 is rotatably supportedby the support member 20. The roll 18 is rotatably supported by thesupport member 22, said roll 18 being drivingly engaged through means 24to a suitable driving means 26.

A spray chamber 28 is defined by walls 30 adapted to provide a suitablearea within which spray equipment may be operatively mounted and withinwhich the fabric may be sprayed. A supply pipe 32 leads to a header 34adapted to feed a plurality of spray nozzles 36, which nozzles 36 aredisposed above the fabric as it passes through the spray chamber 28. Asecond supply line 38 leads to a header 40 which header 40 is adapted tosupply a plurality of nozzles 42 disposed below the fabric as it passesthrough the spray chamber 28. It should be observed that if a relativelynarrow piece of material is being processed through the apparatus, itmay only be necessary to have a single nozzle disposed above and belowthe upper and lower surfaces of the fabric, respectively, in order toassure full spray coverage of said fabric. This is, of course, alsodependent upon the characteristics of the spray nozzle, pressure andother physical characteristics.

Each of the supply lines 32 and 38 is interconnected to a reservoir 44.The reservoir 44 is adapted to store the growth inhibitor solution 46therein for use in the spray chamber, said inhibitor solution being fedto the nozzles 36 and 42 through the supply lines 32 and 38 which definea continuous fluid connection therebetween. A valve 48 may be insertedin the common line leading to the supply lines to. control the flow offluid from the reservoir.

The bottom of the chamber 28 is defined by converging walls terminatingin an outlet 50, which outlet in turn is interconnected to the pumpmeans 52. The pump 52 returns the growth inhibitor solution that fallsto the bottom of the chamber as a result of being sprayed beyond theedges of the cloth, passing therethrough, etc. In this manner optimumutilization of the growth preventative or inhibitor solution is realizedby recirculation to the reservoir 44 through the pump 52 and line 54.

The reservoir 44 may be a pressure container interconnected to a sourceof pressure indicated at 56. The pressure imposed upon the fluid 46within the reservoir 44 propels the fluid to the nozzles 36 and 42. Itshould be observed that pumps may be employed to bring the fluid 46.from the container to the nozzles 36 and 42 in by conventional flatworkironing process well known in the art. It should be observed that theironer S8 is heated to an elevated temperature suflicient to assuretowel flattening. This heat is employed in the present process not onlyto effect the flattening or ironing of the material as it passestherethrough, but also to precipitate the effective growth preventativeagent out of solution.

After the fabric passes through the ironer 58, it is removed from theconveyor 12 and deposited in suitable packaging or storing apparatus forsubsequent processing.

A spray chamber illustrative of the type employed herein is shown incross section in FIGURE 2 wherein a plurality of nozzles 36 and 42 areshown emanating from supply headers said nozzles being effective to passa growth preventative solution therefrom onto the surface of the fabricpassing through the spray chamber 28. The spray from the nozzles shouldbe adjusted to effect complete coverage of the fabric passing throughthe chamber in order to assure the optimum deposition of growthpreventative thereon and optimum protection.

For the purposes of the present invention the spraying chamber 28 andthe ironer 58, in their simplest form need only be a means forapplication (by spraying) of the growth preventative solution to thesurfaces of the fabric so that the solution will effectively permeatethe same and a means for then heating the fabric to precipitate thegrowth preventative thereon and to remove the excess fluid from thefabric. As such, the ironer 58 need only be a heating chamber and wouldbe such if there were no requirement that the fabric being treated besmoothed in the process. It is shown as an ironer in the presentillustration only as it applies to towel laundering serviceapplications, and is not to be construed as limited thereto.

The conventional manner of application of a growth inhibitor to a fabricinvolves the application thereof in the last rinse of the launderingcycle. The effective agent or growth preventative is placed intosolution, in this method, and the solution is then added to the lastrinse of the cycle. The effective agents commonly employed in suchsolutions are phenylmercuric acetate and pentachlorophenol.

The active ingredient, phenylmercuric acetate, for example, is addeddirectly to the last rinse cycle in amounts sufficient to develop theproper solution concentration in combination with the volume of wateremployed in said rinse cycle. The deposition of the effective growthpreventing ingredient upon the surface of the fabric is dependent uponcontact of the fabric with said ingredient during the rinse cycle. Itcan readily be seen that non-uniform deposition of said ingredient uponthe fabric may be achieved during such process due to thecharacteristics of a large quantity of fabric within the rinse bath.Further, the concentration of the ingredient within the solution may notbe uniform and variations in deposition upon the cloth could result inthis manner. In any event, predicability and reproducibility of acontrolled level of deposition of phenylmercuric actate upon the surfaceof the fabric is not to be expected. In View of this fact, the tendencyof the industry is to prepare the solution level of the rinse bath andthe length of the cycle such that a substantially greater level than theoptimum required will be achieved to assure at least minimum depositionupon all of the fabric within the bath. Such a process leads to inherentwaste of materials and is of major concern, especially with therelatively expensive material such as phenylmercuric acetate.

As noted above, when phenylmercuric acetate is employed in the rinsebath of the laundering cycle, the amount thereof that must be added tothe bath to leave an effective concentration on the fabric will dependupon (1) the total volume of water within the rinse bath and (2) theefiiciency of extraction of the effective growth preventative from thesolution. It should be observed that phenylmercuric acetate is notpreferentially absorbed upon the fabric, and thus the deposition of thephenylmercuric acetate upon the fabric after it has been fully processedis a function of the amount of water and solution that is present uponthe fabric and is retained thereon after removal from the rinse cycleand passage through the water extraction cycle. The remainder of thesolution, of course, is disposed of and is washed down the drain. It isto be noted that, under normal conditions, approximately 70% to 90% ofthe phenylmercuric acetate is lost hrough disposal along with theexpended rinse water.

The pentachlorophenol, for example, which is the effective mildicideingredient of sodium pentachlorophenate, is added to the rinse bath inthe present process of treating fabrics in much the same manner as withthe phenylmercuric acetate. The pentachlorophenol (PCP) is added to therinse bath in the form of sodium pentachlorophenate. The PCP is releasedfrom the sodium form in acid solutions. The rinse bath, therefore, mustbe acidified to exhibit a hydrogen ion concentration of approxi matelypH or less. It can readily be seen that the operator of such equipmentmust observe the solution concentration of the rinse bath in order to becertain that the proper pH level is realized and that the level does notvary considerably during the cycle. The PCP will precipitate out onlywhen the solution condition is on the indicated acid side, otherwise itwill remain in solution in the rinse bath and will subsequently bewashed down the drain with the disposal of the rinse water. In actuallaundry operation the preparation of the rinse bath solution to achievethe proper pH concentration is frequently impossible or may not beachieved when desired with the subsequent result that the fabric inprocess is not treated and thus is not rendered resistant to the growthof mold, etc. thereon. It should also be observed that there frequentlywill be large variations in the PCP content on the fabric of discreteitems within the same load being processed. This non-uniform depositionof PCP upon the fabric gives rise to problems. In view of this, it againis necessary to provide a stronger concentration of PCP in the solutionthan would be necessary if the deposition thereof upon the surface ofmaterial were realized in a more efficient manner. The concentration ofthe rinse bath could be realized through the use of sophisticatedcontrol systems adapted for such operation. The addition of such controlsystems to the laundering equipment, however, would render the operationuneconomical. It can readily be seen that if such controls were added tothe processing equipment, not only would the initial investment berelatively high, but additional expenditures would be incurred in thatit would then be necessary to employ an operator capable ofunderstanding and operating equipment supplied with such controls. Suchpersonnel ordinarily are highly skilled people that can commandrelatively high wages for their services. There is, of course, theadditional problem of maintenance of such equipment, which of itself,may give rise to considerable expenditures. In view of the above itseems clear that such equipment is not in accord with that desired foroptimum operation in conjunction with the process herein noted. It thusremains for the development of a simple, inexpensive method applicableto the present process, which method is adapted to apply the growthpreventing means to the fabric in a fashion suitable to protect thematerial.

In one application of the method set forth herein toweling was sprayedto assess the effectiveness of the method and solutions employedtherein.

The toweling was passed through the spray chamber of the apparatus at arate of 60 feet per minute and sprayed with solution under a pressure of40 p.s.i. The fabric or toweiing as fed to the spray chamber was atironing moisture level and was passed directly from the spray chamberthrough a belt ironer. The belt and rollers of the apparatus weresprayed with a silicone solution to avoid water spotting of thetoweling.

After ironing the treated towels were tested for growth resistance byinoculating with various mildew spores and placing them in conditionssuitable for growth for a period of seven days. At the end of thatperiod the towels were examined for growth. It was noted that thosetowels which had been treated with approximately 10 to 20 parts permillion phenylmercuric-acetate exhibited satisfactory resistance togrowth at the end of this period in that very little, if any, towel areawas covered with spores.

Of those towels that had been rinsed in water in a manner that might beexpected to occur in use of the towels, slightly more towel area wascovered with spores.

In accord with the present invention an improved process for applyingthe effective growth preventing agent to the fabric was conceived, whichprocess included spraying of the agent upon the surface of the fabric.

The process of the present invention, generally, involves theapplication of the effective growth preventative to the fabric by aspraying of mildicide solution thereon and then ironing or otherwiseheating the fabric to deposit the efiective preventative ingredient onthe fabric, all of which occurs, of course, after laundering, rinsingand extraction of excess fluid from the fabric.

In the most economical form of application the eifective agent employedin the process is pentachlorophenol (PCP). The active form of thecommonly used growth preventative sodium pentachlorophenate ispentachlorophenol (POP). It is highly desirable that this agent bepresent on the fabric as PCP rather than as its sodium salt for tworeasons. Initially, PCP appears to be a more effective growthpreventative agent than its sodium salt, and second, PCP is waterinsoluble and it will not be removed from the fabric when it is rinsedin water during use.

In view of the fact that the PCP is insoluble in Water it wasimpractical to attempt to obtain a suitable solution there-of foreffective application by spraying on the fabric. Emulsions of PCP aregenerally unsatisfactory as such emulsions generally are diflicult tohandle in spraying.

Due to the fact that PCP is insoluble in water it is put into solutionas its water soluble salt. The sodium salt is converted to PCP underacidic conditions. When the sodium salt is put into solution theresultant product is basic at least to the extent that the pH level isabove 7. In this form the PCP will not precipitate out of the solutionand further solution modification is required to put it in form suchthat subsequent precipitation of the PCP can be realized to make itavailable for deposition upon the fabric. It was necessary, in order toadapt this compound to a spraying application, to develop a compoundthat could be applied in a one-step procedure so that it may exhibit itsmildicide action. The method generally in use heretofore involved a twostep procedure of applying the sodium salt and then changing it to thefree phenol form by application of acid. This procedure is generallyunsatisfactory for application to the treatment of fabric in thatcareful control of the two step process is required, the disadvantage oftreating materials with free acid and the necessity of handling freeacid.

In order to achieve this, the solution of the present invention includesa chemical that is inert at ambient temperatures but becomes an acidwhen heated thereby to provide the conditions requisite for release offree PCP. One such chemical is gluconolactone, but it should be observedthat others may be employed for this purpose. One such other material issodium dihydrogen pyrophosphate which may be substituted forglucono-delta-lactone as the delayed action acidulating agent in thesolution to be sprayed upon the surface of the fabric. It should also beobserved that different levels of acidulating agent may be employed inthe solution the minimum requirement for any given solutionconcentration being set at the amount necessary to give completeprecipitation of the pentachlorophenol from solution upon application ofheat to the solution treated fabric. Such latent acids are 7 effectivein the process of laundering toweling, as presently practiced, in thatthe solution is sprayed upon the fabric after extraction of watersucceeding the last rinse of the laundering cycle and then the fabric isprocessed through a fiat work ironer during which portion of the cyclethe solution is heated to a level sufficient to activate the latentacid, to render the solution acidic, and to precipitate the PCP upon thefabric.

With the spraying process it can readily be seen that significantvariations in deposition or concentration of the effective growthpreventative upon the fabric may be avoided. Effective and uniformamounts of the growth preventative are applied to the surface in aninexpensive and economical fashion. There is no requirement for delicatecontrol of the process in order to achieve optimum results and to thatextent the inadequacies of the prior process for the application ofgrowth preventatives have been obviated. The solutions employed in thepractice of the process are very stable, can be compounded prior to usein the process and will remain in the effective form for indefiniteperiods of time. The concentration of the effective growth preventativewithin the solution is predetermined and controlled during compoundingof the solution and thus the operator need not be concerned with suchconcentration, as heretofore practiced, during processing of every bath.Additional economies of operation are effected in that complete use ofthe solution is realized. Whatever material is not sprayed upon thefabric by, for example, going beyond the edges thereof, or simply beingexpelled therefrom in the spray chamber, is collected at the bottom ofthe spray chamber and recirculated to the storage reservoir forsubsequent use. Thus, the solution is not lost down the drain as wascharacteristic of the prior practice.

Use of a mildicide such as phenylmercuric acetate in the process of thepresent invention generally is slightly less economical than whenemploying PCP as the mildicide. Phenylmercuric acetate is more expensivethan PCP.

In one test of the process disclosed herein, the fabric was passedthrough the spray chamber and solution was sprayed thereon, the amountof solution comprising approximately 1l%, by weight, of the dry weightof the cloth. It was discovered that effective control of growth uponthe fabric could be utilized by using a solution containing about 35ppm. (parts per million) of phenylmercuric acetate. It was further notedthat effective results were achieved with the use of spray tips (in thespray chamber) wherein the nozzle disposed above the fabric as itprogressed through the spray chamber delivered 0.030 gallon of solutionper minute and the nozzle disposed below the fabric as it progressedthrough the chamber delivered 0.077 gallon per minute, both at apressure of 40 p.s.i. with a belt speed for the above given values atabout 60 feet per minute. It should be observed that each of the abovenoted conditions are interrelated and are given as representative ofonly one effective combination suitable for the present process. thervariations may be realized, many of which may be equally effective inachieving the desired result.

The use of pentachlorophenol as the growth preventative in the presentprocess dictated that the solution be prepared such that the PCP be insolution when sprayed upon the fabric. The insolubility of PCP in watersolutions, of course, makes direct solution of PCP impossible. In viewof this fact the solution of the present invention was developed whereinPCP as its sodium salt (which is readily soluble in water solutions) isdissolved in water and a chemical added to the solution, which chemicalis inert in cold solutions but becomes an acid at elevated temperatures,such chemicals being commonly referred to as latent acids. To thisextent the one such chemical involved is an acid salt of lactone whichdoes not make its acid available in solution until heated to atemperature slightly in excess of 200 F. Two such specific chemical E5agents that may be employed are glucono-delta-lactone and sodiumdihydrogen pyrophosphate as delay action acidulating agents.

Glucono-delta-lactone, for example, hydrolyzes as the temperature israised to release gluconic acid which in turn reacts with the sodiumpentachlorophenol of the solution to give sodium gluconate and freepentachlorophenol, the latter being the effective growth preventative.

In the process disclosed herein, the solution hereinabove identified issprayed upon the surface of the fabric as it passes through the spraychamber, sufficient amounts being sprayed thereon to saturate thefabric. The fabric is then conveyed to the ironer, which is adapted, conventionally, to smooth the fabric as it passes therethrough. The levelof heat within the ironing operation is sufficient to raise thetemperature of the solution deposited on the cloth to a level in excessof that required to release the acidulating agent within the solutionand to thereby effectuate precipitation of free PCP from the solutionupon the fabric. It should be observed that the process disclosed hereinis readily adapted to many other uses wherein a growth preventative mustbe added to a material. It is not essential that it be launderedmaterial since the laundering thereof, while characteristic of theexample noted herein, is not essential to performance of the novelprocess disclosed. The steps of spraying of the solution containing theeffective growth preventative therein upon the surface of the fabric andthen heating the fabric to precipitate the ECP therefrom may be adaptedfor many applications. For example, it may be desirable to treat fabricin bolts in a textile plant where the bolts are to be stored underconditions conducive to the promotion of growth. In such case thematerial might be sprayed with the solutions noted herein duringprocessing and passed through a suitable heating chamber to heat thesolution on the cloth thereby releasing the acidulating agent andpermitting precipitation of the PCP. It should be noted that the processand product noted herein may also be employed in the treatment of paperand paper products to prevent growth thereon during periods of storage,for example. Paper for newsprint, or the like, usually is stored afterprocessing and before use and must be treated with a suitable growthpreventative in order to protect the product from deterioration prior touse. Paper may be processed in the manner set forth herein to assureprolonged protection of the fiber for periods of storage underconditions conducive to growth of mildicides or the like.

The solution disclosed herein is useful in applying a growthpreventative to fabric and includes sodium pentachlorophenate which isstable at ambient temperatures but which precipitates pentachlorophenol,an effective bacteriocide or mildicide, at elevated temperatures.

Pentachlorophenol is insoluble in water, although the sodium salt,sodium pentachlorophenate is readily soluble in water solutions. Thesodium salt, however, exhibits much poorer bacteriocidal and mildicidalactivity than does pentachlorophenol and in such form is generallyundesirable. The most desirable solution, for spraying purposes, is onewhere the PCP is in solute form at ambient temperatures for sprayingupon the fabric and may be precipitated out of solution at a later pointin processing so as to deposit the effective growth inhibitor, PCP, uponthe fabric. Such compositions are not available in the form that wouldnot deleteriously effect the material to which the solution will beapplied.

The present disclosure provides for an alkaline solution of sodiumpent-achlorophenate in combination with an acid salt which salt does notmake its acid available in solution until heated. In such form theeffective growth preventative may be precipitated from solution byraising the temperature of the solution thereby releasing theaeidulating agent and creating an acidic solution condition suitable forprecipitation of the effective growth preventative therefrom.

The pH level of the solution preferably is controlled within the rangeof pH 10 to pH 11 with suitable alkaline compounds. However, the pH isnot critical and can be varied without impairing the useful form of thesolution. The pH preferably is kept on the basic side to assure thatpremature precipitation of the PCP will not occur.

Several solution concentrations were employed in the process set forthherein during tests of the solutions and process. For the conditionsindicated hereinabove, that is, for a belt speed of about 60 feet perminute with a spray pressure of 40 p.s.i. it was found that solutionconcentrations of about 0.05% to about 0.07% pentachlorophenol weresufficient to assure satisfactory growth preventative deposits of activePCP upon the surface area of the toweling being treated. The solutionconcentrations would, of course, be varied in accord with spray andtransport rates each of the various elements being interrelated foroptimum treatment of the toweling.

One solution that was prepared for use in spraying fabric and that wasfound to be effective in use employed 1.45 grams of sodiumpentachlorophenate which was dissolved in 1000 milliliters of water,then 1.50 grams of glucono-delta-lactone were added and the mixture wasstirred until a clear solution resulted. The solution was then broughtto a pH level of 10.3 with a 0.5 N sodium hydroxide solution.

Upon heating this solution to approximately the boiling point of water,pentachlorophenol precipitates therefrom and may be used to coat afabric.

Varying solution concentrations may be achieved, for example, bydilution of the above noted solution to the desired concentration.

While the invention has been set forth specifically herein it will, ofcourse, be understood that other modifications may be used withoutdeparting from the true spirit and scope of the invention. It isintended by the appended claims to cover all such modifications as fallwithin their true spirit and scope.

What we claim as new and desire to secure by Letters Patent of theUnited States is:

1. A process for depositing pentachlorophenol uniformly on fabric inprecipitate form which comprises the sequential steps of spraying saidfabric with an aqueous, alkaline solution containing sodiumpentachlorophenate and glucono-delta-lactone and then ironing saidfabric to concomitantly smooth the fabric and deposit pentachlorophenolthereon in precipitate form throughout the fabric.

2. A process for depositing pentachlorophenol on a fabric in precipitateform including the steps of spraying said fabric with an alkalinesolution containing sodium pentachlorophenate and glucono-delta-lactoneand then heating said fabric and the soution thereon to hydrolize saidglucono-delta-lactone to release gluconic acid, said gluconic acidreacting with the sodium pentachlorophenate of said solution to providefree pentachlorophenol on said fabric.

3. A process for depositing pentachlorophenol on a fabric in precipitateform which includes the steps of spraying said fabric with an alkalinesolution containing sodium pentachlorophenate and glucono-delta-lactoneand then heating said fabric to deposit pentachlorophenol in precipitateform throughout the fabric.

4. A process for depositing water insoluble bacteriocide on a fabric toprevent growth of bacteria thereon comprising applying to said fabric anaqueous solution containing sodium pentachlorophenate as a solublebacteriocide and glucono-delta-lactone as a latent acid adapted torelease an acid compound upon application of heat thereto and attemperatures above a select level and heating said fabric and solutionto a temperature above said level to cause the released acid to reactwith the soluble bacteriocida and precipitate the water insolublebacteriocide pentachlorophenol on said fabric.

References Cited by the Examiner UNITED STATES PATENTS 2,483,008 9/49Higgins 1l7-l38.5 XR 2,548,646 4/51 Bicknell et al. 117l38.5 XR

WILLIAM D. MARTIN, Primary Examiner.

1. A PROCESS FOR DEPOSITING PENTACHLOROPHENOL UNIFORMLY ON FABRIC INPRECIPITATE FORM WHICH COMPRISES THE SEQUENTIAL STEPS OF SPRAYING SAIDFABRIC WITH AN AQUEOUS, ALKALINE SOLUTION CONTAINING SODIUMPENTACHLOROPHENATE AND GLUCONO-DELTA-LACTONE AND THEN IRONING SAIDFABRIC TO CONCOMITANTLY SMOOTH THE FABRIC AND DEPOSITE PENTACHLOROPHENOLTHEREON IN PRECIPITATE FORM THROUGHOUT THE FABRIC.